It's about six times as heavy as a Beer Keg
In other words, 0.000000420 megatonnes is 5.7690 times the weight of a Beer Keg, and the weight of a Beer Keg is 0.17330 times that amount.(for US half-barrel, full keg; draft beer; including keg itself, stainless steel)
A typical, half-barrel beer keg weighs 0.00000007280 megatonnes when full. A keg of this size contains 15.5 gallons of beer, or the equivalent of 6.8 cases.
It's about one-fifth as heavy as The Tongue of a Blue Whale
In other words, 0.000000420 megatonnes is 0.160 times the weight of The Tongue of a Blue Whale, and the weight of The Tongue of a Blue Whale is 6.30 times that amount.(Balaenoptera musculus) (adult)
The tongue of a Blue Whale can weigh up to 0.00000270 megatonnes. Despite their tremendous size, blue whales feed almost exclusively on tiny crustaceans called krill and cannot swallow anything much larger than a beach ball.
It's about eight-and-a-half times as heavy as an Octopus
In other words, the weight of an Octopus is 0.120 times 0.000000420 megatonnes.(for Giant Pacific Octopus, Enteroctopus) (Adult, average)
The adult North Pacific Giant Octopus usually weighs around 0.0000000500 megatonnes. It is the largest octopus species and is known for its considerable intelligence, including the ability to open jars, solve mazes, and mimic other octopuses.
It's about one-tenth as heavy as a Hippopotamus
In other words, 0.000000420 megatonnes is 0.1120 times the weight of a Hippopotamus, and the weight of a Hippopotamus is 8.930 times that amount.(Hippopotamus amphibius) (adult, male)
The average weight of an adult male hippopotamus ranges from 0.000003750 megatonnes. Appearances to the contrary, adult hippos cannot swim or float in water; they actually move by leaping and walking across lake bottoms at about 8 kph (5 mph).
It's about nine-and-a-half times as heavy as a Toilet
In other words, 0.000000420 megatonnes is 9.630 times the weight of a Toilet, and the weight of a Toilet is 0.1040 times that amount.(KOHLER Round front sitting flush toilet, model #K-11471-0)
The weight of a typical round front sitting flush toilet is 0.00000004360 megatonnes. The Indian town of Musiri in Tamil Nadu state features the world's only paying toilet, which rewards its users up to 10¢ Indian (10 paisas) per visit and uses the waste for compost and fertilizer.
It's about fourteen times as heavy as a Dalmatian
In other words, 0.000000420 megatonnes is 14.20 times the weight of a Dalmatian, and the weight of a Dalmatian is 0.0704 times that amount.(a.k.a. Dalmatinac, a.k.a. Carriage Dog, a.k.a. Spotted Coach Dog, a.k.a. Firehouse Dog) (FCI standard; male)
The Fédération Cynologique Internationale (FCI) calls for Dalmatians to weigh between 0.00000002950 megatonnes. The association of the breed with fire departments (and similarly with Budweiser Beer and its team of Clydesdales) stems from their affinity for horses, having been used historically as carriage dogs capable of guiding horse-drawn fire engines to the sites of blazes.
It's about one-fifteenth as heavy as an Elephant
In other words, the weight of an Elephant is 14 times 0.000000420 megatonnes.(for African bush elephant, Loxodonta africana) (Adult, bull)
A bull African bush elephant weighs about 0.00000610 megatonnes. Among African elephants, both males and females have tusks (whereas female Asian elephants, Elephas maximus, do not have tusks) which can grow to 3 m (10 ft) and typically weigh about 0.00000400 megatonnes